Earth’s oceans are older than the sun says a new study published in the journal Science. “The Ancient Heritage of Water Ice in the Solar System” asserts that the chemical make-up of earth’s oceans prove the water derived from someplace outside the solar system. If earth’s water came from interstellar ice, there is a high likelihood that most planetary systems have water and may support life. Many people assume water has always been part of the earth, but as scientists learned more about how the solar system and earth formed, they began to question the presence of water.
The sun formed nearly 5 billion years ago from an immense cloud of gas and dust that was much larger than the entire solar system today. As the dusts and gases condensed at the center of the cloud, the whole thing began to spin. Eventually, enough material accreted to begin nuclear fusion, releasing electro-magnetic energy, including heat and light. The formation of the sun also formed rotating proto-planetary disks. These swirling fields of debris came together, crashed apart, and came together again many times to create the planets and other planetary bodies. Denser material near the sun formed the inner planets as rocky spheres. Lighter material flung away from the spinning star formed the giant gas orbs of the outer planets. It was a chaotic time with material moving into and out of the sun’s growing gravitational pull.
The early earth was a round chunk of hot rock – not a conducive environment for water. So why is 75 percent of the planet’s surface covered by liquid H2O? One theory is that the constant volcanic eruptions released gases which started to form the earth’s early (toxic) atmosphere. The most abundant element in earth’s rocks is oxygen. Hydrogen is the most common element in the universe and also extremely abundant on earth. The oxygen and hydrogen gases combined and water rained down from the skies for thousands of years until the earth’s interior began to cool and quieted and the oceans filled.
Except, scientists running models for this theory discovered that there was no way for all the water on earth to have been created this way. There is just too much water for all of it to be accounted for from gases trapped in rock and millennia of rain. No other practical phenomenon for creating water on earth exists, so scientists began considering that not all water had an earthly origin.
Recent studies of comets and asteroids have found that water is not unique to planets. It actually permeates the solar system. Scientists realized it is possible that one or more asteroids carrying vast amounts of water crashed into the early earth releasing its liquid bounty. Scientists wanted to know if this water was created by chemical reactions during the formation of the solar system or was already part of the cloud from which the sun formed.
The new study on the origins of water makes the startling revelation that some of the water on earth is older than the sun. Not only did it come from someplace off the earth, it came from somewhere outside of the whole solar system. The scientists examined the ratio of hydrogen to deuterium. Deuterium is an isotope of hydrogen, sometimes called heavy hydrogen because it contains an extra neutron. Water created in the solar system exhibits specific deuterium-to-hydrogen enrichments caused by the low temperature of the original molecular cloud that birthed the sun. It was created under the same conditions in the proto-planetary disks and so exhibits the same characteristics. The proportion of deuterium to hydrogen provides important clues about the conditions under which water molecules formed. Interstellar ice has a higher deuterium-to-hydrogen ratio. By comparing the numbers scientists can tell if water formed during the birth of the solar system, or before it.
The researchers used computer models to compare the deuterium-to-hydrogen ratio over time. They found levels of heavy hydrogen inconsistent with the conditions of the formation of the solar system. Much of the water on earth and throughout the solar system must have already existed in the original molecular cloud. The researchers determined that 30 to 50 percent of earth’s waters predate the sun. Nearly half the water on earth is one million years older than the solar system.
The study has further implications for finding distant planets with water and life. Study author Ilsedore Cleves from the University of Michigan says that water would be a “common ingredient” in the universe. Conel Alexander, from the Department of Terrestrial Magnetism at the Carnegie Institute agrees. The implication is that water, possibly carrying pre-life material, is traveling throughout the universe and embedding in planetary systems rather than arising from them. This abundant interstellar ice may be available to all planetary systems. Life may be even more common, and perhaps more similar, than previously estimated.
Earth’s oceans are older than the sun and may indicate abundant life among the stars. As much as 30 to 50 percent of the planet’s water predates the solar system by 1,000,000 years. If water, the source of life, found its way to earth, it is likely a regular feature in many other planetary systems as well.
By: Rebecca Savastio